Senny HD575's

[G a f f e r]

Right, loads of Q's here so bear with me.

Do these 'phones actually exist?
Do I have some kind of third party fake made in PROC?

The reason I ask is:
a) I can't find ANY info on them either on the web or even on Sennheiser's website (are they ashamed of them? )
b) they sound Terrible compared to my previous pair (can't remember the model, I think they were HD480 mkII.....dark grey.....fabulous 'phones that had a great balance. I only got rid of 'em because the wires degraded over the years and Senny didn't make replacements by then (that and one of the diaphragms started to crackle, but i had 6 years good use from 'em).
Anyway these 575's have Way too much treble.
I have fixed this by placing a sheet of tissue paper into the cup and edging it under the foam rim to keep it in place. They now sound about right, so i'd give them an 8/10 (bass is great and detailed, more midrange shines through, because the tissue has tamed the overbright treble).
So what are they (I call them "Symphony's" 'cos I don't know the name) and where can I get info on them?

Finally, If i don't like bright treble (hate my current iPod Sony mdr-ex71slw's more and more btw), can anyone recommend a decent pair of not too piercingly high headphones that sound as good (in the same vein as) my old HD480 II's and cost around the same as my current shortlist of Sennheiser HD580, Grado SR80, AKG 270, Beyerdynamic DT990 ?

Is this a good spread to choose from and are there any others worth considering?
I plan to use them for my home seperates system and buy a creek OBH21 to drive them (don't think the MF XCANv3 worth the extra £100?).
I'll get rid of my 575's if I can get a decent set of replacements.

thanx for any help